Nitrogenous esters



I y-w United. st tes Pa f'Q V 3 Claims. Cuzco-+ 153 The present invention relates to nitrogenous esters and more particularly provides a new and valuable class of formimidat'es, the method of prepariugthe same, and bio logical "toxicants comprising the formimidzites.

According to the invention "there are provided certain alkyl N-dichlorophenylformimidates by the reaction of alkyl orthdf'ormates with dichloroanilines, substantially according'toth'e scheme:

in which R is an alkyl radical' of from :1 to .5 carbon atoms;

.Alkyl N-dichlorophenylformimidates a having the above formula and provided thy the a'nventi'on'are, e.-g., methyl N 2,3 dichlorophenylformimidate, methyl N 3,4 idichlorophenylforrriimidate, "methyl N-SJS-dichlorophenyllformimidate, ethyl N 2;6f-'dichlorophenylformimidate,

, 1etl1yl N12,3=dichlorophenylformiinidate,' ethyl N-2,4-dichlorophenylformimidate, n proplyl 'N-"3g4-dichlorophen- 'ylformimidate, fisopr'opyl t1NQfi-dichlorophenylforiniinidate, n-'but-yl N-2,3-dichlorophenylformimidate, isobutyl 'N-B,5*dichloroplienylformimidate, .n-am'y-l'-N 3.,4-dichlorophenylformimidate, 'n-amyl N-2;6-dichlorophenyIform- 'imidate, 'isoarnyl' N-2,'5=dichlorophenylformimidate, etc.

Dichloroanilines which are 'reacted with appropriate alkyl :orthofor'mates includes 123- 33,4- 2,6- 2,-4- 3,5- and 2,5-dichloroaniline. The presently useful alkyl orthoformates are methyl, ethyl, :n-ipropyl, isopropyl, n-butyl, isobutyl, n-amyl, andisoamyl' orthoformates. I

According to the invention'the'present alkyl N -dichloro- :phenylforimidates :are' prepared by contacting the appropriate dichloroaniline with the appropriate alkyl orthoformate at ordinary or increased temperatures and in the presence or absence of an acidic agent as catalyst. Thus, the reaction may be eflected by simply mixing the two reactants and-catalyst, in the presence or absence of an inertdiluentorrsolvent, and heating the resulting mixture at a temperature oflfrom, say, 40 C. to the refluxing temperature. ZSince preparation of the present formim'idaltes involves condensation of one mole of the dich'loroaniline with one mole of the orthoformate, the

reactants may be advantageously @u's'ed in equimolar proportions; however, an excess of the alkyl orthofo'rinate is generally useful inthat it serves as ajreaction'diluent and at the same time makes for adequateavailability'of the 'orthoformate whereby formation of by-product amidines is minimized. rExcess alkyl orthoformate, when employed, 1is readily 'rem'ovedwfrom the reaction product,.e;g., by distillation. g t

. Qperationflin-the presence ;of acidic catalysts, generally, is advantageous. As examples of useful catalysts may be mentioned acid reacting salts such as cuprous or cupric, stannous or stannic, .ferrous or ferric acetates, sulfates or chlorides, organic or inorganic acids such as acetic, oxalic, benzenesulfonic, 4-toluene-sulfonic, sulfuric, hydrochloric or phosphoric acid, etc.

As shown in the abovereaction -scheme, condensation of one mole of the jdiclil'o'rtjam'jlifn'e with one 'mole of the alkyl orthoformate takes place with the formation of 2 moles of an alkanol as a by-product. This may be removed from the reaction product after the condensation has been completed; but, more conveniently, provision for-collecting the alkanol during the reaction is made'by-conducting the reaction by reflu ng temperature in-apparatus comprisinga distilling condenser and/or trap, whereby the volatilized alkanol is removed as it is formed; Progress of the reaction maythus be determined by noting the quantity of 'alkanol collected. 1 When the reaction is effected in thepresence "Of {an acidic catalyst, treatment of the reaction product with a base maybe employed in order to neutralize theacid content thereofprevious to isolation of the formimidate product. However, .such a neutralization step is not necessary,,particularl:y when substantially equimolar proportions of the'dichloroaniline and alkyl orthoformate had been used initially, In the presence-,of excess dichloroaniline, however, the neutralization step may serve to minimize subsequent reaction of the formimidate product duringuan isolation .step which may involve distillation. fAs be apparent to those-skilledin the art, the procedure employed for isolating the formimidate will depend upon the presence or absence of by-product alkanol, reactant excesses, etc. Generally when substantially *equim'olar quantities of the dichloroaniline com ponent and the alkyl orthoformate component have been employed, the reaction has been carried to completion, and the alkanol has been condensed oil, the reaction product comprises the 'substantiallypurfe alkyl N-dichlo'rophenylformimidate. When the presence of alkanols,

other by-prcducts, or unreacted reactants is suspected in the reaction mixture, the formimidate is readily recovered from the crude reaction :product by isolating procedures customarily employed in theart, e.g., by solvent extraction or distillation. I 1 I I The present alkyl N-diehlorophenylformimidates are stable, well characterized compounds which are advantageously employed for a variety of commercial and agricultural purposes, e.g., as lubricant additives, as plasticizers for synthetic resins and plastics, etc. As will be shown hereinafter they are particularly valuable as herbicides and as fungicides.

The invention is further illustrated, 'but not limited, by the following examples:

Example 1 3,4-Dichlo'roaniline '(8l.0';g., 0.59 -mole) was mixed with '11l.0 g. (0.75 mole) of freshly distilled ethyl orthofor'mate, four drops of concentrated sulfuric acid was :During the refluxing "44.9 'g. of byproduct ethanol was collected. When the. reaction mixture had cooled -to C.,, as was neutralizedwith anhydrous potassium carbonate, and unreacted ethyl o'rthoformate (37. 8 g?) Found Calcd. for

, CoHnClzON Example 2 A mixtureconsisting of 81.0 g. (0.59 mole) of 2,5- dichloroaniline, 111.0 g. (0.75 mole) of freshly distilled ethyl orthoformate and 4 drops of concentrated sulfuric acid was heated to refluxing within 35 minutes, and refluxing was continued at a pot temperature of 8-7-91 C. for about 1.5 hours and then for an additional 1 hour and 22 'minutes at a pot temperature of 91-146 C. During the refluxing 45.4 g. (98.5% of theory) of byproduct ethanol was collected. After allowing the reaction mixture to cool to 74 C., it was treated with 2 g. of potassium carbonate.- Unreacted ethyl orthoformate (37.1 g.) was stripped oif the reaction mixture at waterpump pressure and the residue was distilled to give 90.9 g

g. (82.6% theoretical yield) of the substantially pure ethyl N-2,5-dichlorophenylformimidate, 'b.p. (pot temperature)'106148 C./1.4-4.0 mm., which solidified in the receiver to a white to pale yellow solid, softening at about 45 C., melting at 51-53 C., and analyzing as Example 3 The ethyl N-3,4-dichlorophenyl formimidate of Example 1 and the ethyl N-2,5-dichlorophenylformimidate of Example 2 were tested against the fungi Aspergillus niger employing the following testing procedure:

' Respective 1% stock solutions of each of said formimidates in a non-toxic solvent were made up, and these solutions were respectively added to containers of sterile, melted Dextrose agar in quantities to give 1 part of formimidate per 1,000 parts of agar. After thorough mixing, the respective agar mixtures were poured into Petri dishes and allowed to harden. One drop of a spore suspension of the fungus served as inoculum for each plate. perature of 25 C., for 5 days. At the end of that time inspection of the dishes showed completeinhibition of growth of the test fungus, whereas controls, i.e., Petri dishes of agar containing no test chemical but similarly inoculated and incubated showed extensive fungus growth.

Example 4 This example shows testing of the ethyl N-2,5-dichlorophenylformimidate of Example 2 against the bacteria Microcococcus pyog'enes. var. aureus and Salmonella typhqsa. The 1% stocksolution of Example 4 was respectively added, to melted nutrient agar to give a test mixture containing 1 part of test compound per 1,000

The inoculated plates were incubated at a temparts of agar. Petri dishes were filled with each of the test mixtures, and the plates thus prepared were then inoculated with the test organisms and incubated for 2 days at a temperature of 37 C. At the end of that time inspection of the plates showed complete inhibition of growth of both the M. pyogenes and the typhosa organisms by each of the two test mixtures, whereas contro inoculated nutrient agar plates showed profuse growth.

Example 5 corn, barnyard grass, crabgrass and pigweed were scattered over the surface. The seeds were then covered with the soil mixture to the top of the pans. To furnish a uniform nutrition level and to prevent insect infestation, the pans were next sprayed with 30 cc. of an aqueous solution containing 1% of a liquid fertilizer and 0.1% of octamethylpyrophosphoramide. Finally,

the pans were sprayed respectively with 30 cc. of herbicidal compositions prepared by dissolving 0.4 g. of one of the formimidates designated below into 20 cc. of acetone and diluting a 10 m1. aliquot of the resulting acetone solution with water to 30 cc. Application of this quantity of solution to one of said flats is calculated to correspond to the use of 25 lbs. of the formimidate per acre. The flats were then placed in A" of water and allowed to absorb moisture through perforated bottoms until the soil surface was completely moist. The flats were then transferred to a wet sand bench in the greenhouse and maintained there for two weeks.

Observation of the flats at the end of that time showed that in the flat which had been sprayed with the ethyl N-3,4-dichlorophenyl formimidate only the corn had emerged and was flourishing; complete suppression of all of the other plantings had been effected in this flat. On the other hand, in those of the pans which had been sprayed with either ethyl N-S-chlorophenylformimidate orethyl N-phenylformimidate, there was no evidence of harmful effect, all of the seeds having germinated into seedlingswhich showed no evidence of phytotoxic effect.

The above test shows ethyl N-3,4-dichlorophenylformimidate to possess a most interesting selective effect; at the test concentration it can be used to de-weed a field planted to corn without injury to the corn.

The present alkyl dichlorophenylformimidates may be applied as fungicides or herbicides by any suitable method, for example as sprays or as dusts comprising an inert carrier which may be a liquid or powdered solid. When used as sprays they may be employed in solution or in emulsion form. I have found that oil-in-water emulsions of the alkyl N-dichlorophenylformimidates possess an improved tendency to adhere to the treated organism and that less of the active ingredient, i.e., the alkyl N-dichlorophenylformimidate, is required to give comparable fungitoxicity or contact herbicidal effect. The emulsions are readily prepared by first preparing a solution of the N-dichlorophenylformimidate in an organic solvent and then adding the resulting solution to water containing an emulsifying agent to form an emulsion. Emulsifying agents which may be employed are those customarily used in the art for the preparation of oil-in-water emulsions. The word oil is here used to designate any organic liquid which is insoluble in water. Examples of emulsifying agents which may be used include alkyl benzene sulfonates, long chained polyalkylene glycols; long chained alkyl sulfosuccinates, etc.

in which R is an alkyl radical of from 1 to 5 carbon atoms.

2. Ethyl N-3,4-dichlorophenylformimidate. 3. Ethyl N-2,i-dichlorophenylfonnimidate.

References Cited in the file of this patent UNITED STATES PATENTS Goldsworthy June 4, 1940 Horst Oct. 8, 1940 Horst Nov. 12, 1940 Glickman July 27, 1954 

1. A COMPOUND OF THE FORMULA 